Two-cycle internal-combustion engine



3y i946@ H. FORSTER TWO-CYCLE INTERNAL-COMBUSTION Filed March l5, 1945 ENGINE Patented July 30, 1946 TWO-CYCIE INTERNAL-COMBUSTION ENGINE l Henry Forster, Broadviewglll Application' March 15, 1945; Seriali No. 582,855

9 Claims.

My invention which relates toA two-Cycle engines primarily has for its object to provide improved means for supercharging the crank case with workable mixture.

Further it isV an object to provide a simple, effective and inexpensive means which is especially adapted for use in model engines used on model airplanes, etc. Enginesof the kind just referred to usually employ a rotary valve for controlling the fuel admission to the crank case and my inventionfinvolves the use of a combined rotary valve and compressor unit which not only controls the fuel admission but also assists the piston to compress a greater charge than that usually drawn into the crank case for compression by the piston'` Again it is an object to provide an improved means to increase the volume of the crank caseV while the piston is on its suction stroke and, after the crank case has been filled with working mixture by the suctionV of the piston; force the increased volume of fuel into the normal crank case space to be compressed by the piston on its compression stroke.

Other objects will in part be obvious and' in part be pointed out hereinafter.

To-the attainment of the aforesaid objects and ends the invention also resides in those novel details of construction, combination and'arrangeu ment of parts all of which shall be first fully described hereinafter `and then be` specifically pointed out in the appended claims, reference being had to the accompanying drawing in which:

Fig. 1 is a central vertical longitudinal section of an engine' embodying' my invention.

Fig. 2 is a detail side elevation of the rotary valve with the pistondisc omitted;

Fig. 3 is an end elevation of the saine.

Fig. 4 is a detail cross section on the line 4-4 of Fis'. 3;

In the drawing in which like numerals Yof reference indicate like parts in all the figures, I represents the cylinder of an engine of the type hereinbefore mentioned. The piston 2 carries a wrist pin 3 to which one end of a connecting rod 4 is pivoted, the other end ofthe rod 4 being pivoted to the crank I0.

The crank case 5 is preferably cast integrally with the cylinder I and has one end wall provided with a bore I4 for a purpose presently ex#- plained. The crank case has a shaft bearing 6, suitably bushed as at 'I to receive the crankshaft 8. The shaft 8 has a crank disc 9 and the crank IIJ. The crank Iil isV hollow and is bushed at II to receive the crank 32 of the rotary valve.

A piston-controlled by-pa'ss I 2Y conveysv the compressedA mixture from the crank case into the cylinder I above the piston. The exhaust port andduct is shown at I 3; l

The valve-compressor housing I S has a reduced end I5 which iits tightly into the bore I4 and the cylinder I3 is;l securedto the crank case by cap screws I 8- passing through bores in the crank case: and tapped intoears II on the cylinder IS. The housing I6- is. divided into two parts by a V-shapedincross-section partition 2I the inner face Ilof` which is a plane surface inclined upwardlyeinwardly while the outer face 20 inclines upwardly-outwardly, the angles of inclination ofthe faces I9 and 20 are the same.

22` indicates the fuel intake duct whose fiared end 23A admits air. A gasoline nozzle 24 held in a bossv 25 supplies the combustible and with the air constitutes the fuel which passes down the duct to thevalve sleeve Z'I.l

The valve sleeve 2 has a port 23 to register with the lower end of the intake duct 22 at times. lt also has ports 29 communicating with the space between the partition 2I and the piston disc 35 that is secured to the threaded end 33 of the closed end of the valve sleeve, a jamblnut 33 being provided to prevent the pistondi e 35 coming loose.

At the open end the sleeve 2'! is provided with a disc 3l that moves asa piston in the innermost bore of the cylinder IB while the disc 33 acts as aI piston in the outermost bore of the cylinder 6.

A ball 33 is mounted on the disc 3'! and carries a shoe 34 that lies against the face I9 of the partition while a ball 3l is mounted on the disc 35 at the side diametrically opposite that where the ball 33 is locaterLand carries a shoe 38 that lies in contact with theface 2D of the partition 2 I.

As the crank shaft 8 rotates' during its norma] operation, it rotatesand drives, by means of the crankpin 32, the rotary valve.. The rotary valve, dueto the two ball joints 33 and. 3l and shoes 34 and 38, acting on the stationary cam (the V-shaped partition 2l)` is forced to move axially in a reciprocating manner. At: a prede termined position of the crankshafti port 28in the rotary valve, communicates with the carburetter intake (tube 22)V for admission of the fuel mixture. With the crankshaft rotation conn tinuing, the rotary intake port 28` closes, Whereupon the-rotary valve, movingin an axial direction toward the crankshaft; decreases-the volume of the crankshaft spa`ce39. i

The four ports or passages 29 in the rotary valve communicate with the crank case through the hollow rotary valve shaft (sleeve 21), in consequence of which the resultant added volume of gases to the crank case per revolution for supercharging amount to two times the area of the greatest diameter of the rotary valve multiplied by its axial movement.

From the foregoing description taken in connection with the accompanying' drawing it is thought the construction, operation and advantages of the invention will be clear to those skilled in the. art.

What I claim is:

1. In a two-cycle internal combustion engine'.

having a cylinder, a crankcase, a piston and a crank shaft employing crankcase compression and wherein the fuel mixture is admitted to the crankcase and through a rotary valve, the improvement which comprises: Van extension to the' crankcase, said extension being in communication with the crankcase at one end of the extension, a rotary valve in said one end and serving as a closure therefore; means to move said rotary valve axially in said one end to increase and decrease the effective capacity of said crankcase;

and means to passV fuel into the crankcase via said valve at suitable times.

2. In a two-cycle internal combustion engine having a cylinder, a crankcase, a piston and a crank shaft and employing crankcase compression and wherein the fuel mixture is admitted to the crankcase by' and through a rotary valve, the improvement which comprises: a combined rotary and reciprocating valve; a housing for said valve in which the valve is rotatably andreciprocatingly mounted, said housing being in part functionally an extension of said crankcase; means to pass fuel into the crankcase via said valve when said valve is in one position; and means to rotate and reciprocate said valve by virtue of which the effective Vcrankcase volume will alternately be increased and diminished for purposes described.

3. In a Vtwo-'cycle internal combustion engine having a cylinder, a crankcase, a crank shaft, a piston operatively connected with said crank shaft, and means for delivering fuel to the crankcase, the improvement which includes a body havingl a cylindrical passage divided into two chambers by a suitable partiti-on that is in turn provided with a valve-sleeve bearing; a rotary valve in said body and comprising two end discs,

one located in each chamber and connected by a sleeve open at its end adjacent the crankcase and closed at its other end against atmosphere, said sleeve adjacent said other endhaving ports communicating with the second of said chambers at places betweensaid partition and the adjacent end disc; a fuel mixing and delivering duct in said partition communicating with said valve sleeve, said valve sleeve having a port to register with said fuel duct at times; and means to rotate and simultaneously reciprocate said valve.

4. In a two-cycle crankcase-compression engine having a cylinder, a crankcase, a piston, a crank shaft and a pistoni-od, said crankcase having a `valve-controlled fuel inlet, the improvement which includes: a valve-compressor cylinderI said valve-compressor cylinder having a V-shaped partition with a valve-sleeve bearing and dividing said valve-compressor cylinder into two chambers, one of Vwhich chambers communicates directly with the interior `of the crankcase and the other chamber is remotefrom the crankcase;

a combined valve and compressor-piston in said valve-compressor cylinder and including two end piston-discs connected by a sleeve one end of which communicates constantly with the cranky duct and to super-charge the crankcase with fuel at times.

5. The engine of claim 4 wherein the means to rotate said combined valve and compressor-piston on its axis and reciprocate it along its axis comprises shoes on said discs for engaging the respective faces of said V-shaped partition, and means to rotate said valve.

6. In a two-cycle crankcase-compression internal combustion engine having a cylinder, a piston, a crankcase, a crank shaft and a connecting rod; the combination with the aforesaid structure of means for admitting fuel to and supercharging the crankcase withA fuel, said means including a fuel duct; an auxiliary cylinder connected to the crankcase; a combined fuel admitting andl fuel charging valve in said auxiliary cylinder, said valve having a fuel passageway and a port for registering with Vsaid fuel duct; and means to turn said valve on its kaxis and move the valve along its axis for purposes described.

7. The engine of claim G wherein the .means to turn said valve on its axis and move the same along its axis comprises a crank pin` on said combined valve and operatively connected through said crank shaft for turning said valve and c am means to reciprocate said valve along its axis as the valve is being turned.

8. In a two-cycle crankcase-compression internal combustion engine having a cylinder, a piston, a crankcase, a crank shaft and a connecting rod; the combination with the aforesaid structure of means for admitting fuel to and supercharging the crankcase with fuel, said means including a fuel duct; an auxiliary cylinder connected -to the crankcase; a combined fuel admitting and fuel charging valve in said auxiliary cylinder', said valve having a fuel passageway and a port for registering with said fuel duct; and means to turn said valve on its axis and move the valve along its axis for purposes described, said last named means comprising a crank pin yon said combined valve, operatively connected to said crank shaft for turning said valve and cam means to reciprocate said combined valve along its axis as it is being turned, said oam'means comprising a V-shaped member having a valve bearing in which said combined valve rotates, said combined' valve including end vdiscs and shoe-carrying elements swivelly mounted on each disc and engaging said V-shaped member at diametrically opposite points. 4

9. In a two-cycle crankcase compression engine; means to control the admission of fuel into the crankcase and supercharge the same, said means including a combined rotary valve and fuel charger unit and means to operate the same to charge additional fuel into the crankcase` 'on the compression stroke of the engine.

, HENRY, FORSTER i 

